U.S. patent number 4,432,541 [Application Number 06/296,684] was granted by the patent office on 1984-02-21 for recirculating document feed apparatus and method for aligning documents therein.
This patent grant is currently assigned to International Business Machines Corporation. Invention is credited to William D. Clark, Mark D. Garner, John H. Rhodes, Jr., Bernard L. Wilzbach.
United States Patent |
4,432,541 |
Clark , et al. |
February 21, 1984 |
Recirculating document feed apparatus and method for aligning
documents therein
Abstract
A document feed device, illustrated with a copier machine, for
recirculating documents through a processing station. A movable
portion of the document feed device is mounted for pivoting
movement to expose a lower document feed path. The movable portion
contains several document moving rollers but no prime movers, gears
or belts; these rolls are driven by frictional contact with each
other and ultimately by contact with a set of driven rollers
located in the nonmoving portion of the document feed device. The
rollers comprising a document moving nip are oppositely skewed
relative to the direction of document travel in order to move
documents gently toward a reference edge and coefficients of
friction of roller materials are chosen to insure correct document
alignment.
Inventors: |
Clark; William D. (Longmont,
CO), Garner; Mark D. (Boulder, CO), Rhodes, Jr.; John
H. (Longmont, CO), Wilzbach; Bernard L. (Berthoud,
CO) |
Assignee: |
International Business Machines
Corporation (Armonk, NY)
|
Family
ID: |
23143090 |
Appl.
No.: |
06/296,684 |
Filed: |
August 27, 1981 |
Current U.S.
Class: |
271/251;
271/301 |
Current CPC
Class: |
B65H
9/166 (20130101) |
Current International
Class: |
B65H
9/16 (20060101); B65H 009/16 () |
Field of
Search: |
;271/251,301,272,273,274 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
IBM Tech. Disc. Bulletin, vol. 24, No. 1B, Jun. 1981, pp. 808-809,
"Recirculating Document Feed with Dual Entry Gate", by W. D. Clark
et al. .
IBM Tech. Disc. Bulletin, vol. 24, No. 1B, Jun. 1981, pp. 821-822,
"Scanning Fiber-Optic Bundle Copier with Recirculating Document
Feed", by W. D. Clark et al..
|
Primary Examiner: Schacher; Richard A.
Attorney, Agent or Firm: Rohrer; C. E.
Claims
What is claimed is:
1. The method of aligning the side of a document against a
reference edge which is located parallel to the direction of
document travel, and in which said document is moved through the
nip of rollers in which said document may slip while it is being
moved toward the reference edge, comprising the steps of:
skewing a first roller on the drive side of the nip to the
direction of document travel in a manner to provide a force
component away from said reference edge;
skewing a second roller on the nondriven side of the nip to the
direction of document travel in a manner to provide a force
component toward said reference edge so that when said document
slips on said first roller it tends to follow said second roller
toward said reference edge; and
providing said second roller with a lower coefficient of friction
than said first roller to avoid crumpling said document when it is
against said reference edge.
2. The method of claim 1 in which the skew of said first roller is
set close to zero degrees so that said document is not driven too
far away from said reference edge during that portion of document
travel when it does not slip in said roll nip.
3. The method of claim 2 in which the skew of said second roller is
substantially greater than the skew of said first roller.
Description
This invention relates to a recirculating document feed device and
more particularly, to a device which includes a pivoting portion
containing no prime movers and a method for aligning documents
despite slippage in document moving roll nips.
BACKGROUND OF THE INVENTION
Paper moving schemes appearing in the art are numerous and include
such devices as vacuum belts, vacuum trays, wave generators, large
diameter rollers, soft high friction rollers, hard high friction
rollers, and leading edge pullers. Means of moving, turning, or
transporting said devices include chains, belts, blowers, etc.
driven by a prime mover such as a motor.
In recirculating document feed devices, a document is passed
through a processing station and then recirculated so that it
passes through the processing station again. The cycle can be
repeated any number of times until the desired number of processing
steps have been completed. Recirculating document feed devices
ordinarily use paper moving schemes involving gears and belts, etc.
such as described above and as illustrated in U.S. Pat. No.
3,661,383. Such systems are subject to difficult document retrieval
should a jam occur, they are costly relative to the invention to be
described herein, and are difficult to adjust and maintain.
The instant invention involves a configuration in which it is
possible to drive an entire system of paper moving devices by
providing only one set of driven rolls directly connected to a
prime mover and using frictional contact between those rolls and
additional sets of freely rotating rollers to obtain document
recirculation. The freely rotating rollers are positioned in a
pivoting frame which opens to expose the document feed path to
provide for ease of document retrieval, ease of mechanism
adjustment, ease of maintenance and easy book copying. This
arrangement provides a reliable low-cost drive which is quiet and
safe because of its freedom from belts, chains, or gears. This is
also important from a safety viewpoint since recirculating document
feed devices are in an area of user access.
An additional advantage of the invention is the ability to bias the
side of a moving document against a side reference edge with a
controlled force so as not to crumple the edge of the document by
making use of the principles described in U.S. Pat. No. 4,179,117.
In an especially innovative and advantageous design, the invention
incorporates a large freely rotating roller which forms a part of
two roll nips in two different document feed paths and thus creates
unusual problems in document side edge referencing in both paths.
The invention herein solves that problem.
Additionally, the beam strength of documents when driven around the
substantially 180.degree. bends of a recirculating document feed
path creates slippage in roll nips and therefore unusual problems
in maintaining alignment of the document against the side reference
edge. Moreover, a document in two roll nips may be pulled through
one nip by the other, again creating an unusual aligning problem.
The invention herein provides a method for solving these
problems.
SUMMARY OF THE INVENTION
This invention is embodied in a document feed device which includes
a first set of roll nips provided in a first document path, the
roll nips comprised of driven rolls and a first set of freely
rotating rollers. The driven rolls are placed on the underside of
the first document path protruding slightly above the plane of the
path to individually mate with individual ones of the first set of
freely rotating rollers which are thereby powered through contact
with the driven rolls. A reference edge is provided along one side
of the document feed path to provide a surface for referencing
documents. The drive rolls and the first set of freely rotating
rollers are skewed to the direction of document travel to urge
documents against the reference edge.
The document feed device further includes a second document path
for receiving documents from the exit of the first path and
returning them to the entrance of the first path. The second
document path contains a second set of roll nips comprised of two
groups of freely rotating rollers. The first group of freely
rotating rollers is situated on the underside of the second
document path and each roller protrudes slightly into the plane of
that path to mate individually with individual ones of the second
group of freely rotating rollers. The second group of freely
rotating rollers are powered through contact with the first group
of freely rotating rollers which are powered ultimately by contact
with the driven rolls. The first and second groups of freely
rotating rollers are skewed to the direction of document travel in
the second path to urge documents into a second reference edge
positioned along one side of the second document feed path.
The document feed device contains a movable cover portion mounted
about a pivot to expose the first document feed path, thus breaking
the first set of nips when opened. When opened, none of the freely
rotating rollers can operate since the only source of power is
connected to the drive rolls which are not a part of the movable
portion.
In a particular embodiment, large rollers are provided to form a
part of both the first and second set of roll nips, that is, the
large roller mates with a drive roll to form one of the first set
of nips in the first document path and also extends into the second
document feed path to mate with a roller of the second group of
freely rotating rollers to form one of the second set of nips. In
this embodiment, the driven rolls are skewed between zero and 0.4
degrees for urging a document away from the first reference edge,
while the first set of freely rotating rollers, the large rollers
are skewed between zero and 0.6 degrees for urging documents toward
the first reference edge. The coefficient of friction of the first
set of freely rotating rollers may be chosen to be greater than the
coefficient of friction of the drive rolls.
In this particular embodiment, by virtue of the fact that the first
set of freely rotating rollers protrude into both document feed
paths and urge the document toward the reference edge in the first
document feed path, it moves the document away from the second
reference edge in the second document feed path. The second group
of freely rotating rollers, therefore, should have an angle of skew
and a coefficient of friction relative to the first set of rollers
such that a proper alignment of the document is maintained in the
second path. This requirement is met in the described embodiment in
an unusual manner since the coefficient of friction of the roller
urging the document toward the reference edge is substantially
lower than the coefficient of friction of the mating roller. This
method of arranging the rollers is advantageous due to slippage of
the document in the roll nip during document movement toward the
reference edge and allows the document to follow the lower friction
roller when slippage is occurring on the higher friction roller.
This results since the document, when slipping, will follow the
roller on the nondriven side of the nip.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a recirculating document feed device containing the
instant invention positioned on a small compact copier machine.
FIG. 2 is a schematic diagram showing the recirculating paper path
of the embodiment of FIG. 1, together with the major elements of
the copier machine.
FIG. 3 shows the document feed device of FIG. 1 pivoted to an open
position exposing the lower document feed path.
FIG. 4 is a perspective drawing of a partial sectional view of FIG.
2 showing the skewing arrangement of drive rolls and freely
rotating rollers in order to urge document alignment with the
reference edges.
DETAILED DESCRIPTION
The document feed device of this invention is useful in many
environments but is illustrated in this detailed description in
conjunction with a document copier machine in order to explain its
features and its value.
FIG. 1 shows a document copier machine with an exterior housing 10
containing a top surface 11 inclined at an angle of approximately
20.degree. to the horizontal. Positioned on that top surface is a
document feed path 19, the sides of which are generally defined by
reference edge 13 and spine 14. Document feed path 19 forms a part
of a recirculating semiautomatic document feed device (RSADF) 15
together with hinged cover 15' and all associated drive rolls,
freely rotating rollers, and guides. When cover 15' is closed as
shown in FIG. 1, cover 15' and document feed path 19 provide an
entry slot 12 for the insertion of single documents to be copied.
After copying, these documents exit from the RSADF through an exit
slot 17 located in cover 15'.
A paper cassette 35 is shown in place for feeding copy paper into
the machine. The completed copy is returned against the face 40 of
the cassette.
FIG. 2 is a schematic drawing showing the interior side view of the
copier machine of FIG. 1 illustrating the document path 18 of the
recirculating semiautomatic document feed device 15. FIG. 2 also
shows the copy paper path 36 from cassette 35 and the various
processing stations located along photoconductive belt 20.
A document to be copied is manually inserted through input slot 12,
where it is sensed and driven to queuing gate 44. If no other
document is being copied, gate 44 is released allowing the document
to advance to registration gate 46. When the machine is ready, gate
46 is released allowing drive rolls 48 and 50 to move the document
across the fiber optic viewing station 16. The original document,
after processing, is either delivered to the exit slot 17, or is
recirculated for multiple copies by return paper path 18 as
determined by the position of gate 63. Gate 63 is automatically
positioned in accordance with the number of copies selected by the
operator and a count of the number of copies already produced from
that original document.
The image of the original document thus scanned is placed upon a
continuous loop photoconductor (PC) belt 20, which is retained in
place by means of a guide frame assembly 21.
The copier machine shown in FIG. 2 takes an electrophotographic
two-cycle process configuration wherein corona 25 operates as a
charge corona to place an appropriate electrostatic voltage level
on PC belt 20. The image of the original document is placed upon
belt 20 at imaging location 26 by selective discharge, based upon
the information contained in the original document. This image is
then developed by developer unit 30 which places toner on
appropriate areas of belt 20 as it passes the magnetic brush roller
31.
The paper gating mechanism 34 controls the introduction of copy
sheets from cassette 35 to the photoconductor belt 20 in
appropriate synchronism with the movement of the toned image on
belt 20. Corona 24 operates as a transfer corona to transfer toner
from belt 20 onto the copy sheets. The copy sheets continue to the
fuser comprised of rollers 38 and 39 where the toner image is fused
to the copy sheet. The toned copy sheet is then exited from the
machine.
FIG. 3 shows the machine of FIG. 1 with the cover 15' of the
recirculating document feed device 15 rotated around the hinges 41
to an open position. In this position, the entirety of the document
feed path 19 along the top surface 11 is exposed to view. FIG. 3
shows document feed path 19 with a document reference edge 13 along
one side and a spine or rail guide means 14 positioned along the
opposite edge. Entry sensor 42, aligner roll 43, queuing gate 44
and registration gate 46 precede viewing station 16 in paper feed
direction A. All document moving rolls protrude above the plane of
top surface 11 with rolls 45, 47, 48, 49 and 50 lying within path
19 and rolls 52, 53 and 54 located across the rail guide means 14
outside of the document path.
The open cover 15' in FIG. 3 shows the corresponding rollers 43',
47', 48', 49' and 50' which mate with the rolls on the top surface
11 to form roll nips when the cover 15' is closed. The open cover
in FIG. 3 also exposes a manual start button 51 for use when
copying books.
When a single sheet is to be copied and document feed cover 15' is
in place, entry switch 42 automatically starts machine operation
when the document is sensed, and aligning roll 43 operates to
position the single sheet against reference edge 13 and queuing
gate 44. After alignment, and if there is no preceding sheet in the
device 15, gate 44 is dropped and mating rolls 43 and 43' move the
paper down the feed path 19 in direction A to registration gate 46.
At the proper point in the machine cycle, gate 46 is dropped
allowing rolls 43, 47 and 48 to move the document across a
stationary elongated document viewing station 16, the major
dimension of which is perpendicular to feed path direction A. Rolls
49 and 50 continue to move the document out through exit slot 17 or
around through the return paper path 18 if multiple copies are to
be made.
If multiple copies are being made, the sheet recirculates through
document path 18 shown in FIG. 2 until it returns to gate 46.
Again, at the proper point in the machine cycle, gate 46 will drop
initiating another copy sequence. During this period of
recirculation, a next sheet can be inserted by hand to aligning
roll 43 and moved against the queuing gate 44. In that manner, once
the required number of copies have been made of the first document
and it has exited through slot 17, gate 44 will drop allowing the
second document to proceed to gate 46 and repeat the cycle.
Rolls 45, 52, 53 and 54 together with spine 14 are provided for
copying books as more fully explained in U.S. patent application
Ser. No. 296,683.
A comparison of FIGS. 1 and 3 show that the document feed device 15
contains a lightweight, easily movable cover portion 15' pivoted by
hand to an open position by grasping cover 15' at hand grip 60.
This ease of movement is made possible by the fact that none of the
rollers mounted in the pivoting cover 15' are driven except through
contact with the drive rolls when the cover is closed. As may be
observed in FIG. 3, this provides an added safety feature since
none of the rollers 43', 47', 48', 49' or 50', which are exposed
when the cover 15' is open, are driven when the machine is used for
copying a book along the exposed paper path 19.
Referring now to FIGS. 2 and 4, the drive mechanism for
recirculation of documents is illustrated. Drive rolls 48 and 50
are positioned on the underside of first document feed path 19
protruding slightly through the plane of that path to form a first
driving nip with freely rotating rollers 48' and 50'. In the
embodiment illustrated, the latter rollers are large in
circumference and extend upwardly to protrude slightly into second
document feed path 18 to form a second nip with freely rotating
rollers 48" and 50". Exactly the same construction is present for
roller groups 49, 49', 49" and 47, 47' and 47" so that the groups
of rollers form sets of nips, a first set of nips in document feed
path 19, and a second set of nips in second document feed path
18.
A drive motor 62 is shown in FIG. 4 connected to drive roll 48.
Suitable connecting transmissions, not shown, connect motor 62 with
the other drive rolls. Motor 62 may also drive other components
within the copier machine if desired. It should be noted that in
the embodiment shown in FIGS. 1-4, the nonpivoting portion of
document feed device 15 is a part of the copier machine itself,
that is, the first document feed path 19 is coincident with the top
surface 11 of the copier machine 10.
In operation, a paper is fed by hand through entry slot 12 and
after queuing at gate 44 and registering at gate 46 as previously
described is fed into that portion of document feed path 19
containing the rollers 47 and 48. These rollers with the associated
freely rotating rollers 47' and 48' move the document across
viewing station 16 and into the nip of rollers 49, 49', and 50,
50'. If multiple documents are to be made, the document is
recirculated into the second document feed path 18 where the
document is fed in direction B through the rollers 50', 50" and
49', 49" and into the nips of rollers 47', 47" and 48', 48". The
leading edge of the paper is then fed around bend 61 and back into
first paper path 19 to register against gate 46 prior to beginning
the next cycle.
As may be appreciated, it is important to maintain proper document
position against reference edge 13 while the document passes across
the viewing station 16. As a consequence, rollers 48 and 48' are
skewed to direction A, that is, the direction of document movement
along paper path 19 so that the paper is urged toward reference
edge 13. FIG. 4 shows that roller 48' is positioned at an angle
such that it tends to drive the paper toward reference edge 13
while roll 48 is skewed to direction A in a manner such that it
tends to urge the document away from reference edge 13. In a
preferred embodiment, roller 48' is positioned at an angle between
zero and 0.6 degrees into the reference edge, while the drive roll
48 is positioned at an angle between zero and 0.4 degrees away from
the reference edge. One can be assured that the document will be
moved toward the reference edge if roller 48' is caused to have a
higher coefficient of friction than roll 48. The advantage of
skewing roll 48 to urge the paper away from the reference edge is
that this provides control over the force moving the paper into the
reference edge and thus prevents a crumpling of the paper when it
engages with edge 13. It should be understood that once the
document edge is aligned against the reference edge, slippage in
the roll nip must occur to keep the document from crumpling and
thus control over the forces moving the document into the reference
edge is important. Again, that subject is fully discussed in
above-referenced U.S. Pat. No. 4,179,117.
As one can appreciate from FIG. 4, when large roller 48' is
positioned to urge paper toward reference edge 13 in paper path 19,
it results in moving paper away from reference edge 13' when the
paper is moving in second document feed path 18. Thus, freely
rotating roller 48" is skewed to the direction of document movement
B to urge the documents towards reference edge 13'. Again, by
choosing the coefficient of friction of roller 48" to be greater
than roller 48', one can be assured of moving the paper toward
reference edge 13'. However, in a preferred embodiment of this
invention, roller 48" is chosen to take a lower coefficient of
friction than roller 48' for the following reasons. As paper is
moved around bend 61, the beam strength of the paper tends to cause
a high drag force in the nip of rollers 48', 48" which tends to
create slipping in the roll nip. When slipping, the document tends
to follow the roller on the nondriven side of the nip and thus the
leading portion of the document is correctly positioned against the
reference edge by skewing roller 48" toward the reference edge.
This is advantageously accomplished by a low friction roller since
it is important to limit the force moving the document into the
reference edge once the document is against the reference edge.
Slippage between the document and the roller on the nondriven side
of the nip must occur at that point to avoid crumpling the
document.
When the leading edge of the document has passed around bend 61 and
enters the nip of rolls 48 and 48', it tends to be pulled through
the nip of rollers 48' and 48" thus again creating slippage at that
nip. As a result of that slippage, the document again tends to slip
on roller 48' which is on the drive side of the nip (although not
itself directly driven) and to follow the lower friction roller 48"
on the nondriven side of the nip. Thus the trailing portion of the
document is correctly positioned against reference edge 13' and the
low coefficient of friction of roller 48" prevents document
crumpling at the reference edge.
In a preferred embodiment, roller 48' is positioned between zero
and 0.6 degrees in a manner tending to urge the paper away from the
reference edge in the second paper path 18 while freely rotating
roller 48" is skewed at an angle between 1.degree. and 15.degree.
to the direction of paper movement tending to urge the document
toward the second reference edge 13'. A representative coefficient
of friction may be 0.6 to 1.5 for roller 48' and 0.4 or less for
roller 48". A similar analysis can be made for rollers 47' and
47".
Thus, a recirculating document feed device has been described which
requires no driven components in a hinged cover and in which
documents are successfully aligned against reference edges for
accurate copying even though slippage is present in roll nips while
the document is being moved toward the reference edge. There are
modifications to the embodiments described which might be made at
one's discretion. For example, the single large rollers 47', 48',
49' and 50' could be replaced by a plurality of rollers and various
skewing arrangements might be attempted with different device
dimensions and/or configurations.
While the invention has been particularly shown and described with
reference to a preferred embodiment thereof, it will be understood
by those skilled in the art that the foregoing and other changes in
form and details may be made therein without departing from the
spirit and scope of the invention.
* * * * *